Umlagerungen von 5,5,6,6‐Tetraalkyl‐2‐norbornyl‐Kationen

Rearrangements of 5,5,6,6‐Tetraalkyl‐2‐norbornyl Cations When the 6,6‐dimethyl‐2‐norbornyl cation (9) is generated from the tosylhydrazone 5 by way of the diazonium ion 8, a 2H label is distributed equally between positions 1 and 2 of the exo‐alcohol 10. The degeneracy of 9, previously derived from solvolytic studies, is thus confirmed for the deaminative route. 5,5,6,6‐Tetramethyl‐2‐norbornanone (25) and tetracyclo[4.2.2.12,5.01,6]undecan‐3‐one (31) are prepared by using Diels‐Alder methodology. The corresponding tosylhydrazones 26 and 32 are employed as precursors for the 5,5,6,6‐tetramethyl‐2‐norbornyl and tetracyclo[4.2.2.12,5.01,6]undec‐3‐yl cations (11 and 12). Again, the distributions of 2H labels are close to 1 : 1. The angular distortions expected from repulsive interactions of the methyl groups in 11 and from cyclobutane annulation in 12 do not affect the relative energies of the bridged ions.